Aquafin produces CO2-neutral biogas from wastewater

The sewage treatment plant of Aquafin in Antwerp produces biogas made from wastewater. The gas is purified and then injected directly into the natural gas network. It’s a Belgian first. The new biomethane facilities were officially inaugurated on Thursday by the Flemish Minister of Energy, Zuhal Demir (N-VA). Thanks to the new production process, Aquafin opens up new potential to produce a CO2-neutral fuel that is always available.

The treatment plant uses sewage sludge in a fermentation process. Sewage sludge contains many organic substances: micro-organisms that biologically decompose wastewater. The result is a green gas, which in its turn, is upgraded to the same quality level as natural gas. In term, the process will provide 500 families with green gas.

Purification

At first, the biogas is not clean enough to be directly injected into the gas network. Therefore, it needs to be purified. The purification process happens in several stages, including cooling, extracting moisture, purification with activated carbon filters, and separating methane and CO2 by a membrane system. The Dutch Bright Biomethane treatment unit is responsible for the final cleansing.

At the end of the process, a specific odor is added to detect the gas in unsafe situations. Before the gas is injected into the gas network, the last step is quality control.

Sludge from purification processes is already used to produce electricity by burning it, but the direct production of usable gas is a Belgian first. On top of that, the process is more energy-efficient, since there is no lost heat.

Green gas

Minister Demir is enthusiastic about Aquafin’s initiative. “People associate green electricity with solar and wind energy, but waste can be a great source of green energy too,” she said during the inauguration. “The local production of green gas from wastewater has many advantages. It means we will import less fossil fuel and burn less waste, reducing CO2 emissions.”

The newly produced gas is available as an alternative to natural gas. It can also be offered in other forms, like Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG). “What all these green gases have in common is that they will play a crucial role in the decarbonization of our economy,” concluded Didier Hendrickx, Public Affairs Manager Gas.be.

Aquafin’s biomethane unit is the first in Belgium to draw gas from biomethane coming from fermented sewage sludge. The innovative project is realized with the support of the Flemish government.